Blinding: Each patient after enrollment will be assigned a serial number consecutively after meeting inclusion criteria reviewed by the principal investigator and research assistant. After the necessary workup and consent, drug shall be obtained from the AKUH pharmacy. The pharmacy will carry out randomization and deliver either alprostadil or normal saline (placebo) in an unmarked vial. Delivery dose and frequency will be carried out similarly for all patients. Data will be collected by the research assistant and nurse. At the end of the trial (after all cases and controls have been enrolled) the serial numbers of the patients will be matched to the delivery chart of the pharmacy to see whether they received the drug or placebo.